Provisional Tolereble Weekly Intake:
The Joint FAO/ WHO Expert Committee on Food Additives recommended that
"any use of mercury compounds that in creases the level of mercury in
food should be strongly discouraged". It recommends a provisional
tolerable weekly intake of 0.3mg total mercury per person, of which
no more than 0.2mg should be present as methylmercury.
The Ministry of Health and Welfare of Japan set the tolerable intake
for adults (body weight 50Kg) as total mercury of 0.25mg and methylmercury
of 0.17mg.

National Limits for Mercury in Fish:
As temporary standards, several limits for mercury levels in seafoods
have been proposed to ensure acceptable limits for the average intake
of total mercury.
In Japan, the Ministry of Health and Welfare established provisional limits
for mercury levels in fish and shellfish as follows: total mercury,
0.4MgHg/ g; methylmercury, 0.3MgHg/ g. These levels are not applicable to
river fish, tuma and other prelagic species. Strict application of the
limits are observed for pregnant women.